Method and tool for maintenance of hard surfaces, and a method for manufacturing such a tool

ABSTRACT

A method is disclosed for maintaining a hard surface, the method comprising treating of the surface with a flexible pad ( 1 ), in the presence of abrasive particles, bonded to the pad, on a contact surface between the pad ( 1 ) and the hard surface. The abrasive particles comprise diamond particles, and the treating is performed in the absence of an effective amount of crystallization agent on the contact surface. 
     A tool for use in the method is also provided, as well as a floor surfacing machine comprising such a tool and a method for manufacturing such a tool.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. Ser. No.11/079,081 filed Mar. 15, 2005, the entire content of which isincorporated therein by reference.

TECHNICAL FIELD

The invention relates to a method and a tool for maintenance of hardsurfaces, primarily concrete (cement), terrazzo and granite floorsurfaces, but also marble or limestone surfaces. The inventionparticularly relates to a method and a tool for maintenance which issuitable for use on a daily basis to maintain a polished hard floorsurface.

BACKGROUND

It is known in connection with cleaning or light polishing of floorsurfaces to use a pad in the form of a three-dimensional non-woven web.The pad is usually provided as a circular, disc-shaped body, which is tobe disconnectably mounted on a circular carrier plate, which in use iscaused to rotate in a plane parallel with the floor surface, such thatthe pad, when brought into contact with the floor surface, is slightlycompressed by the pressure arising between the floor surface and thecarrier plate. The carrier plate is usually driven by a motor and may bemounted on a carrier frame, which may be arranged to be pushed or pulledby a walking operator or which may be arranged as a ridable vehicle.

Such pads are generally formed from fibers of an organic material, e.g.polyamide and/or polyester, particularly polyethylene terephtalate. Insome cases the fibers also include natural fibers, such as walnut fibersor coconut fibers.

The fibers of the pad are generally interconnected at their mutualpoints of contact by so-called melt bonding, whereby the fibers aresubjected to heat that cause the outer part of the fibers to slightlymelt and thereby to bond to each other.

Alternatively, or additionally, the fibers may be interconnected attheir mutual points of contact by the pad being impregnated with apolymer resin, hereinafter referred to as a “primary binder”.

Production of this type of non-woven pads is well known from e.g. U.S.Pat. No. 3,537,121, U.S. Pat. No. 4,893,439, EP-A-0 397 374, GB-A-1 348526 and EP-B-0 562 919, and thus does not need to be further elaboratedon herein.

U.S. Pat. No. 3,537,121 discloses pads for polishing surfaces ofaluminum, plastic, wax and similar surfaces. U.S. Pat. No. 3,537,121also discloses production of such pads. In U.S. Pat. No. 3,537,121 abinder mixed with abrasive particles is applied to the pad by passingthe pad between a pair of squeeze rolls, one of which is partiallyimmersed in a container for a mixture of binder resin and abrasiveparticles, after which the pad is allowed to cure or dry. Thus, in U.S.Pat. No. 3,537,121 a pad is provided, which is entirely impregnated bythe binder and abrasive particles.

U.S. Pat. No. 4,893,439 discloses a pad for polishing floor surfaces oraluminum. The pad consists of fibers of organic material and constitutesa lofty open non-woven structure, and contains a binder binding abrasiveparticles to the fibers. The pad shown in U.S. Pat. No. 4,893,493 haslarger voids than that shown in U.S. Pat. No. 3,537,121, and thereby hasan improved ability to absorb dirt, so that it can be used for a longerperiod. Also the pad disclosed in U.S. Pat. No. 4,893,493 is entirelyimpregnated by binder and abrasive particles.

EP-A-0 397 374 discloses a pad for floor polishing machines, which alsois entirely impregnated by binder and abrasive particles.

Pads of the above type are frequently used for so-called “burnishing”,i.e. dry polishing (often on a daily basis) of very lightly wornsurfaces at high speed (1500-3000 rpm) and relatively low pressure, witha view to restoring a polished surface. This type of treatment iscommonly used for both vinyl and marble floorings. Pads suitable forthis purpose are available from 3M™ under the designation “3M™ FloorPads”, and provide no or little effect on very hard floor surfaces, suchas terrazzo or concrete, which have been subject to wear for a longerperiod of time.

EP-B-0 562 919 discloses a non-woven pad of polymer fiber, which isentirely impregnated by a binder comprising a mixture of curable plasticresin and abrasive particles having a particle size of 0.1-30 μm. Asexamples of curable resins are mentioned phenol resin, acrylic resins,melamine resin and urea resin. Diamond is mentioned as one among severalother examples of plausible abrasive particles. However, according toEP-B-0 562 919, the pad disclosed therein is suitable for treatment ofmarble floor surfaces, and only in combination with crystallizationchemicals, which means that treatment must be made in the presence ofliquid containing a salt-forming acid.

The pad in EP-B-0 562 919 is also provided by passing a non-woven padthrough a nip between two squeeze rolls, one of which being partiallyimmersed in a binder/abrasive particles mixture, such that the binderand abrasive particles, via the surface of the cylinder is distributedin the pad.

Since the pad disclosed in EP-B-0 562 919 is to be used in the presenceof crystallization chemicals, the method described in EP-B-0 562 919actually constitutes a vitrification method, used with a view toimproving the stain resistance and durability of a marble floor. Thismethod is not suitable for daily maintenance purposes, since it involvesuse of special crystallization chemicals, including acids, which are toreact with calcium present in the floor surface to form insolublecalcium salts. Such a method is typically used once in connection withthe initial preparation of the polished marble floor, and thereafter atintervals of 6-12 months. The method described in EP-B-0 562 919 is thustoo complicated for being used on a daily basis.

Pads of the type referred to in EP-B-0 562 919 are sold by 3M® under thedesignations “3M^(Tm) 5200 Brown Stone Renew Pad” and “3M™ 4000 GreyStone Polish Pad”, and are used for treating marble in the presence ofcrystallization chemicals and at relatively low speeds (below 250 rpm).

The need for crystallization chemicals makes the polishing work morecomplicated, since the chemicals are to be applied to the surface,possibly followed by removal of excess chemicals, which also contributeto making the polishing work more time consuming. Handling andapplication of the chemicals also constitute a potential hazard to theenvironment in general and to the work environment in particular.

It is also known to provide a polished stone or concrete surface byusing tools comprising grinding or polishing elements made from aplastic resin mixed with abrasive particles, i.a. diamond particles.Since such elements are fixedly mounted on a usually rotating plate,they do not have the ability to compensate for unevenness in the floor,which may lead to uneven treatment of the floor surface, or toscratching or staining of the floor surface in case such an element isto contact the surface at an excess pressure. Yet another problem isthat debris, such as grains of sand, small stones or metal may get stuckin or near the elements and cause scratching of the floor surface.Finally, this type of tools require special machinery capable ofapplying a higher pressure to the contact surface between the tool andthe floor surface.

WO03/075734 discloses a disc-shaped device for cleaning purposes,comprising a nylon scouring material, which is arranged on a rigid disc,whereby grinding elements containing industrial diamonds are placed inrecesses in the active scouring surface. A disadvantage with the devicedisclosed in WO03/07534 is that it does not eliminate the risk of debrisgetting stuck in or near the grinding elements. Yet another disadvantageis that this tool is complex and therefore more prone to breaking andmore difficult and expensive to manufacture.

Hence, there is a need for an improved and simplified method and toolfor daily maintenance of hard surfaces. Preferably, the method should besimple to use, e.g. by persons who do not have specialist training infloor surface preparation, and the method should be usable withconventional floor surfacing equipment, e.g. burnishing machines, etc.Also, the tools should be easy to manufacture, not too expensive, and itshould be durable.

SUMMARY OF THE INVENTION

It is an object of the invention to provide improved technique, whichwholly or partially eliminate the problems with the prior art methodsand pads. In particular, it is an object to provide a method of treatinga hard surface which is more easy to use and which provides a comparableor better result than the prior art methods.

The invention is based on the idea that abrasive particles in the formof diamond particles provide a polishing effect which is vastly superiorto that achievable with those abrasive particles used in the examplesshown in e.g. EP-B-0 562 919, and that this polishing effect is sosuperior as to eliminate the need for crystallization chemicals.

The invention is defined by the appended independent claims. Embodimentsare set forth in the dependent claims and in the following descriptionand drawings.

Thus, there is provided a method for maintaining a hard surface, themethod comprising treatment of the surface with a flexible pad, in thepresence of abrasive particles on a contact surface between the pad andthe hard surface. The abrasive particles comprise diamond particlesbonded to the pad, and the treating is performed in the absence of aneffective amount of crystallization agent on the contact surface.

The term “diamond” is understood to include natural diamond as well assynthetic diamond, and diamond particles being coated with any suitablecoating, e.g. silver.

The term “effective amount” is understood as an amount that issufficient to achieve a measurable gloss improvement as compared to thesame treatment using a liquid containing no crystallization agent atall. Amounts known to be effective are about 1-2 liters ofcrystallization agent (comprising 2-30% by weight of e.g. magnesiumhexafluorosilicate) per 50 m² of floor surface for a single treatmentoperation. Hence, amounts known to be effective on an ad-hoc basis rangefrom about 0.4 g of magnesium hexafluorosilicate per m² floor surface.However, diluted crystallization agent, e.g. at a ratio of 1:100 is alsoknown to be effective when used repeatedly, e.g. in connection withdaily or weekly maintenance. Hence, amounts known to be effective formaintenance on a regular basis range from about 0.004 g of magnesiumhexafluorosilicate per m² floor surface. It is understood that there areother types of crystallization agents, e.g. zinc hexafluorosilicate,hydrofluoric acid and oxalic acid. The values given above may thus needto be adjusted to apply to the respective type of crystallization agentchosen.

The combination of a flexible pad and diamond particles providescompensation for unevenness in the surface, and distributes the pressureapplied to the pad evenly. Also, this combination, through theflexibility of the pad, considerably reduces the risk of the diamondsscratching the surface.

Using diamond particles as abrasive particles when polishing hard stonesurfaces provides an effect equal to or better than use of conventionalabrasive particles, both in wet and dry conditions. In particular, theuse of diamonds enables the crystallization agent to be abolished,thereby eliminating its handling.

The treatment may be performed substantially in the absence of liquid onthe contact surface, i.e. during substantially dry conditions; or in thepresence of water on the contact surface, i.e. during wet conditions. Inparticular, the treatment may be performed in the presence of water anda cleaning agent on the contact surface, thereby making it combineexcellently with the daily maintenance/cleaning operations.

In one embodiment, the abrasive particles are bonded to the pad by meansof a secondary binder. Hence, no abrasives need to be added whentreating the floor. Specifically, the abrasive particles may be bondedto the pad only in the vicinity of the contact surface. This isadvantageous, since the abrasive particles present in the parts of thepad that are not in contact with the hard surface do not fulfill anyfunction and therefore can be seen as a waste. The abrasive particlesmay have an average diameter of 0.1 to 30 μm, preferably between 0.1 and15 μm and most preferably between 10 and 15 μm.

The abrasive particles may comprise at least one of natural diamondparticles, industrial diamond particles and coated diamond particles.

In one embodiment, the pad that is used comprises an open, lofty, threedimensional non-woven web of fibers. Such webs are available at arelatively low cost and in standard sized adapted for the existingsurfacing machines.

The pad may have a density of less than 40 kg/m³, preferably 20-35kg/m³. Thus, the pad comprises a relatively large amount of voids, intowhich dust, debris and particles may migrate during the treatment. Thus,dust is to a large extent contained in the pad rather than beingdistributed in the area where the treatment is taking place, eliminatingthe need for additional dust collecting equipment. Also, by allowingdebris to migrate into the pad, the risk for scratching of the surfaceis reduced.

The method is particularly suitable for use on a floor surface.

The method is particularly applicable where the surface is a stone orstone-like material having a hardness of about 5 moh or more, preferably6-7 moh. Examples of such surfaces are concrete, terrazzo, granite etc.

The pad, while in contact with the hard surface, may be caused to rotateat a rotational speed of 50-3000 rpm, preferably of 100-1500 rpm.

Furthermore, there is provided a tool for treating a hard surface, thetool comprising a flexible pad having an active treatment surfacepresenting abrasive particles bonded to the pad. The pad presents afirst portion wherein said abrasive particles are present in a firstconcentration, and a second portion having a second, lower concentrationof said abrasive particles, said abrasive particles comprising diamondparticles.

In one embodiment, the second portion is substantially free from diamondparticles.

Since the abrasive particles present in the parts of the pad that arenot in contact with the hard surface do not fulfill any function, padsaccording to the invention can be manufactured at a lower cost.

The flexibility of the pad eliminates or reduces the harmful effectsthat diamond abrasive particles could otherwise have on the hardsurface. Hence, the tool may be used for any hard surface, such assurfaces of wood, laminate, marble, granite, concrete, terrazzo, etc.However, the tool is particularly effective for hard stone or stone-likesurfaces, such as granite, concrete, terrazzo, etc.

In one embodiment, the pad consists of a disc-shaped body having athickness and a first surface, wherein said abrasive particles arepresent on said first surface and down to a depth from said firstsurface, which depth is less than said thickness, such that said firstportion is at said first surface and said second portion is at a secondsurface, opposite said first surface. By leaving the second surface freefrom abrasive material and binder, the attachment of the pad to a Velcrohook connector on a carrier plate is facilitated.

In a second embodiment, the pad consists of a disc-shaped body having athickness and a first surface, wherein said abrasive particles arepresent over less than the entire first surface, such that said firstand second portions are situated adjacent each other at said firstsurface. This second embodiment facilitates migration of dust and debrisinto the pad.

In one embodiment, the pad comprises an open, lofty, three dimensionalnon-woven web, including a plurality of fibers, which are adhered toeach other at their points of mutual contact.

The abrasive particles may be bonded to the fibers of the pad by asecondary binder. Hence, the bonding of the fibers of the pad does notin any way need to be negatively affected by the fact that the abrasiveparticles are only present at the contact surface.

As non-limiting examples, the secondary binder may be selected from agroup consisting of phenol resin, melamine resin, urea resin and epoxyresin.

In one embodiment, the secondary binder forms a plurality of distinctdroplets having a maximum diameter which is smaller than an averagelength between two points of mutual contact of a fiber. Thus, the fibersare not entirely coated by the binder resin, facilitating further themigration of dust and debris into the pad.

The pad may further comprise second abrasive particles selected from agroup consisting of graphite, tin oxide, silicon carbide and aluminumoxide.

The pad is preferably provided in the shape of a circular disc having adiameter between 30 and 100 cm and an uncompressed thickness between 1and 5 cm.

Finally, there is provided a method for manufacturing a pad for treatinga hard surface. The method comprises: providing a pad, and applying, ona first surface of the pad, a mixture of a binder and abrasive particlesincluding diamond, such that said pad presents a first portion whereinsaid abrasive particles are present in a first concentration and asecond portion, having a second, lower concentration of said abrasiveparticles. In one embodiment, the second portion is substantially freefrom said abrasive particles. The abrasive particles may be provided tothe first surface by spraying, rolling or dipping.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 a-1 b show a pad according to a first embodiment.

FIGS. 2 a-2 b show a pad according to a second embodiment.

FIGS. 3 a-3 b show enlarged photographs of a pad according to thepresent invention, before and after the binder and abrasive particleshave been applied.

FIG. 4 a-4 b show a diagram of a pad according to the first embodiment,and an enlargement of a portion of the pad.

FIG. 5 is a schematic sectional view of a floor surfacing machine onwhich a pad according to the invention is mounted.

DESCRIPTION OF EMBODIMENTS

The description will first focus on a tool suitable for use in themethod for maintenance of hard surfaces, subsequently on the method formanufacturing the tool, and finally on the use of the tool formaintenance of a hard surface.

Referring to FIG. 1 a, there is shown a pad 1 made up from an open,lofty three dimensional non-woven web of fibers 2. A first surface ofthe pad 1 has a portion P1 presenting abrasive particles bonded to theweb by means of a secondary binder, i.e. a binder having as a mainpurpose to bond fibers to the web. The pad 1 is circular in shape.Referring to FIG. 1 b, a cross section along the line S1-S2 in FIG. 1 ais shown. As is indicated in FIG. 1 b, the portion P1 presenting theabrasive particles is present at the first surface A and to a depth D,which is less than the thickness T of the pad 1. Hence, at the secondsurface B there is a portion P2, which is substantially free from theabrasive particles and the secondary binder.

When referring to “portions”, it is to be understood as a portions ofthe macrostructure of the pad 1 and not portions of the individualfibers.

Referring to FIGS. 2 a and 2 b, there is shown a similar pad 1, thedifference being that there is a portion P2′ also at the first surfaceA, which portion P2′ is substantially free from the abrasive particlesand the secondary binder.

In both embodiments, the abrasive particles are present throughout thesecondary binder, and the fibers are bonded to each other by a primarybinder and/or by being melt-bonded. A description of the preparation ofa pad 1 according to the embodiment discussed with reference to Figs laand lb will now be given.

As a starting material, circular, disc shaped Glit/Microtron® Tan FloorPolishing Pad having a diameter of 20 inches (51 cm), a thickness of 28mm and a weight of 157 grams was used. Such pads are available fromGlit/Microtron, Wrens, Ga., USA. The starting density of the pad wasthereby 27 kg/m³. FIG. 3 a is a microscope photograph showing the padprior to application of the polymer resin/abrasive particles. From FIG.3 a, it can be seen that the fibers constituting the pad are heldtogether at their points 10 of mutual contact by a primary polymerresin. The pad is flexible and resilient and comprises polyester andnylon fibers.

A homogenous polymer resin mixture was prepared, consisting of 200 g PAresin 52-68 phenol resin (available from Perstorp AB, Perstorp, Sweden),100 g of T-RÖD® ethanol (available from Alfort & Cronholm AB, Bromma,Sweden) and 20 g of LANDS LS600F 4-8 μm diamond particles (availablefrom Lands Superabrasives, Co., New York, N.Y., USA). Just beforeapplication of the mixture, 60 g of 651 p-toluene sulfonic acid (PTS)was added as a hardener.

The resin mixture was sprayed onto a first one A of the surfaces of thepolishing pad, using a standard-type compressed air spray gun (normallyused for spraying paint). The pad with the uncured resin thereafterweighed 173 grams. Subsequently, the pad was placed in a hot air oven atapproximately 120° C. for approximately 20 minutes.

The pad has now assumed the appearance that can be seen from FIG. 3 b,which is a microscope photograph. Globules or droplets 11 of theresin/particle mixture are formed along each fiber, also between thefibers' points of mutual contact. The droplets are so distributed thatthe fibers to which they are adhered are not entirely covered. A moreclear illustration of this is found in FIGS. 4 a-4 b, which show a padas described above with reference to FIGS. 1 a-1 b, and an enlargementof a portion of that pad (FIG. 4 b), wherein droplets 11 ofbinder/particle mixture are attached to the fibers.

In order to evaluate the performance of the pad produced as describedabove, comparative tests were carried out in order to evaluate twodifferent 20 inch (51 cm) pads, prepared as described above: a firstone, referred to as “yellow”, having 7-12 μm silver coated diamondparticles, and a second one, referred to as “green”, having 3-6 μmnormal diamond particles. As a reference, two different commerciallyavailable pads were used: a 20 inch (51 cm) 3M™ 5200 Brown Stone RenewPad and a 20 inch (51 cm) 3M™ 4000 Grey Stone Polish Pad were used, bothavailable from 3M, St. Paul, Minn., USA.

The tests were made on two different surface types: Kolmården marble(marble from the Kolmården area outside Norrköping, Sweden) and K40concrete. Each test was carried out on a surface of about 1 m², using aCoor & Kleever Crystallizer 1250KG floor surfacing machine (availablefrom Coor & Kleever, S.A., Barcelona, Spain) having a single carrierplate adapted for receiving a 20 inch floor pad and rotating at about175 rpm. The test included polishing the surface for about 1 minute/m².The surface gloss was measured at several spots on the area before andafter each treatment using a Sanwal/Cenma IG-310 Glosschecker. The glossvalue in the tables below constitute the average value for each area.High gloss is rated 80-90°. Semi gloss is rated 50-75°. Satin is rated30-45°. Rubbed effect is rated 20-25°. Flat sheen is rated 5-15°.

Each surface was tested both dry and using water as a lubricant.Additionally, the concrete surface was tested using Coor Rosa/K-2crystallizer (available from Coor & Kleever S.A., Barcelona, Spain) aslubricant, i.e. the crystallization chemical mentioned in EP-B-0 562 919as comprising magnesium hexafluourosilicate as crystallization agent.

When testing the 3M™ pads, each surface portion was first treated withthe brown pad and subsequently with the gray pad.

TABLE 1 Tests performed with water as lubricant on Kolmården marble PadBrown Gray Green Initial gloss 17 17 10 Liquid Water Water Water Finalgloss 17 35 30

TABLE 2 Tests performed without lubricant on Kolmården marble Pad BrownGray Green Initial gloss 20 25 28 Liquid No No No Final gloss 25 30 50

From tables 1 and 2, it can be concluded that on marble, which is arelatively soft stone having a hardness of about 3-5 moh, and usingwater as a lubricant, the 3M™ pad combination (brown and gray) provide aslightly better effect, although both the gray and the green padsachieved values falling within the “satin” range. However, during dryconditions, the green pad achieved a remarkable improvement, reachingthe semi-gloss range.

TABLE 3 Tests performed with water as lubricant on K40 concrete PadBrown Gray Yellow Green Initial gloss 30 29 24 35 Liquid Water WaterWater Water Final gloss 29 29 35 46

TABLE 4 Tests performed without lubricant on K40 concrete Pad Brown GrayYellow Green Initial gloss 29 34 30 48 Liquid No No No No Final gloss 3435 48 58

From Tables 3 and 4, it is noted that in wet conditions and on K40concrete, having a hardness of about 6-7 moh, the combination of brownand gray pads did not provide any measurable improvement at all, whereasthe combination of yellow and green pads provided a distinctimprovement. In dry conditions, a small improvement was noted for thesurface treated with the combination of brown and gray pads, whereas amajor improvement was noted for the surface treated by the combinationof yellow and green pads.

TABLE 5 Tests performed with Coor Rosa/K-2 crystallizer as lubricant onK40 concrete Pad Gray Green Initial gloss 41 35 Liquid VMC-Pink VMC-PinkFinal gloss 45 51

From table 5, it is noted that some effect is achievable with a gray padusing Coor Rosa/K-2 crystallizer as lubricant on K40 concrete, and thata somewhat better effect is achievable with the green pad using CoorRosa/K-2 crystallizer as lubricant.

All in all, it is concluded that the pad according to the inventionprovides a noticeable improvement as compared with the prior art. Theimprovement is particularly noticeable during dry conditions and onconcrete.

FIG. 5 is a sectional view of a floor surfacing machine 20 on which apad 1 according to the invention is mounted so as to define a contactsurface 9 with the hard surface 8, which in this example is a floorsurface. The pad 1 is mounted on a driven, rotatable carrier plate 4,which is typically journalled in bearings and thus rotatable relative toa machine body 5, on which a motor unit 6 is arranged. In thisembodiment, the machine has a handle 7, and is thus adapted for beingheld/pushed/pulled by a walking operator. It is recognized that in otherembodiments the floor surfacing machine 20 may be e.g. a ridable vehiclefitted with a carrier plate 4 that is adapted for receiving the pad 1.

The pad 1 and method described above can be used for everydaycleaning/maintenance of polished hard surfaces, such as stone, concreteor terrazzo floor surfaces using a floor surfacing machine such as ascrubber/dryer combination machine, e.g. the Nilfisk CR1300; a singledisc floor maintenance machines (low speed or high speed), e.g. theNilfisk 510B or 545; a burnisher, e.g. the Nilfisk SDH5120, BHS5120 orBHS7014, all of which are available from Nilfisk-Advance, Stockholm,Sweden.

The treatment of the floor surface is typically performed by causing thepad, when in contact with the floor surface, to rotate in a planeparallel with the floor surface. Typical rotational speeds are from 50rpm to 3000 rpm. However, lower or higher rotational speeds are notexcluded.

As is clear from the above, a first embodiment of the pad according tothe invention comprises an open, lofty, three dimensional non-woven web,including a plurality of fibers, which are adhered to each other attheir points of mutual contact by means of a primary binder, and inwhich abrasive particles are mixed with a secondary binder and appliedonly to a first surface of the pad, such that the pad is only partiallyimpregnated by the binder/particle mixture. Alternatively, oradditionally, the fibers may be melt-bonded to each other.

In a second embodiment of the pad, binder/particle mixture is onlyapplied to parts of said first surface. This can be achieved by maskingthose parts of the surface to which the binder/particle mixture shouldnot be applied.

In a third embodiment, the pad is entirely impregnated with thebinder/particle mixture, e.g. by using such squeeze rollers as aredescribed in EP-B-0 562 919. In a variant of this embodiment, arelatively thin impregnated woven or non-woven pad is attached to athicker carrier pad in order to provide the flexibility. According tovariants of this embodiment, a substantially two-dimensional woven ornon-woven web is attached to a thicker carrier pad.

In a fourth embodiment, a three dimensionally woven or knitted pad maybe used, whereby the binder/particle mixture is applied as describedabove.

In a fifth embodiment, the abrasive particles are present in thematerial of the pad. In a first alternative, the pad is a non-wovenfiber pad substantially as described above, with the diamond particlesincluded in the fiber material. In a second alternative, the pad is apolymer foam pad with the diamond particles included in the foamedpolymer material.

In a sixth embodiment, the pad is a polymer foam pad, to a surface ofwhich a binder/particle mixture is applied as described above.

The invention is not limited to the use of phenol resin. Other examplesof suitable resins are melamine, urea, epoxy and polyester resins.

Furthermore, the hardener may be selected from any hardener suitable forthe type of resin selected. Also it is possible not to include thehardener, e.g. by allowing the pad to cure at a higher temperatureand/or for a longer period of time.

Also, the solvent (ethanol was used in the example) is provided merelyto reduce the viscosity of the mixture and thereby to facilitatespraying thereof. Any suitable solvent may be used, and the solvent mayalso be excluded, provided that the method of application so allows.

The abrasive particles preferably include diamond. However, floortreatment pads may be produced according to the principles set forthabove using other types of abrasive particles, or combinations thereof,as well, e.g. those mentioned in EP-B-0 562 919. In particular silvercoated diamond particles have proven to provide good results as well.Naturally, the diamond particles may be combined with other types ofabrasive particles.

It is understood that the pad 1 having secondary binder and abrasiveparticles as described above may be attached to a disc or plate havingan arbitrary connector for being connected to a carrier plate of thesurfacing machine, or that the pad may be directly connectable to thesurfacing machine by means of a Velcro-type hook arrangement provided onthe carrier plate, the hooks of which engage the fibers of the pad 1.Hence, the maintenance tool may be composed of the pad with the primarybinder, the secondary binder and the abrasive particles, possibly withthe addition of dyes or printed areas providing information on the typeof pad, manufacturer, trademark etc.

Alternatively, or additionally, the pad may be provided with a backinglayer.

A pad 1 for polishing a hard surface may be provided as described above.Such a pad may, in one embodiment comprise diamond particles having anaverage size of about 0.1-80 μm. In preferred embodiments, the averageparticle size may be about 0.1-30 μm, about 0.1-20 μm or about 0.1-15μm.

According to another embodiment, a grinding pad may be provided asdescribed above, but comprising diamond particles of a different averageparticle size. For example, a grinding pad comprising diamond particleshaving an average size of about 80-800 μm may be provided, preferably80-600 μm and more preferably 80-300 μm.

1. A method of cleaning a floor surface of a stone material, includingmarble, terrazzo, or polished concrete, the method comprising: providinga flexible pad of an open, lofty, three dimensional nonwoven web offibers having diamond particles bonded thereto on a contact surface anddispersed within the flexible pad; treating the surface of the stonematerial by applying pressure and relative motion between the contactsurface of the flexible pad and the surface of the stone material, inthe presence of only water.
 2. The method as claimed in claim 1, whereinthe flexible pad has diamond particles bonded thereto by a secondarybinder.
 3. The method as claimed in claim 1, wherein the flexible padhas diamond particles bonded thereto only in a vicinity of the contactsurface.
 4. The method as claimed in claim 1, wherein the diamondparticles have an average size of about 0.1-80 μm.
 5. The method asclaimed in claim 1, wherein the diamond particles have an average sizeof about 80-800 μm.
 6. The method as claimed in claim 5, wherein thediamond particles have an average size of about 80-600 μm.
 7. The methodas claimed in claim 6, wherein the diamond particles have an averagesize of about 80-300 μm.
 8. The method as claimed in claim 1, whereinthe flexible pad has diamond particles of an average diameter of 0.1 to30 μm.
 9. The method as claimed in claim 8, wherein the flexible pad hasdiamond particles of an average diameter of 0.1 to 15 μm.
 10. The methodas claimed in claim 9, wherein the flexible pad has diamond particles ofan average diameter of 10 to 15 μm.
 11. The method as claimed claim 1,wherein the flexible pad has diamond particles comprising at least oneof natural diamond particles, industrial diamond particles and coateddiamond particles.
 12. The method as claimed in claim 1, wherein theflexible pad has a density of less than 40 kg/m³.
 13. The method asclaimed in claim 12, wherein the flexible pad has a density of 20-35kg/m³.
 14. The method as claimed in claim 1, wherein the stone materialhas a hardness of about 6-7 moh.
 15. The method as claimed in claim 1,wherein said flexible pad, while in contact with the surface of stonematerial, is caused to rotate at a rotational speed of approximately50-3000 rpm.
 16. The method as claimed in claim 15, wherein saidflexible pad, while in contact with the surface of stone material, iscaused to rotate at a rotational speed of approximately 100-1500 rpm.17. The method according to claim 1, wherein the diamond particles aredispersed within the open, lofty, three dimensional nonwoven web offibers to a predetermined depth from the contact surface of the flexiblepad.
 18. The method according to claim 1, wherein the stone material hasa hardness of at least 5 moh.
 19. The method according to claim 1,wherein the treating is performed by a scrubber/dryer combination floorsurfacing machine.
 20. The method according to claim 1, wherein thetreating is performed by a ridable floor surfacing machine.